1. Field of the Invention
The present invention relates to a reversible thermosensitive recording material capable of recording and erasing images repeatedly by utilizing the property of reversibly changing the transparency from a transparent state to an opaque state depending upon the temperature thereof.
2. Discussion of Background
Recently attention has been paid to a reversible thermosensitive recording material capable of temporarily recording images thereon and erasing the same therefrom when such images become unnecessary. For example, as disclosed in Japanese Laid-Open Patent Applications 54-119377 and 55-154198, there are conventionally known reversible thermosensitive recording materials in which an organic low-molecular-weight material such as a higher fatty acid is dispersed in matrix resin such as a vinyl chloride resin. These according materials reversibly assume a transparent state and a white opaque state, so that an image formed in the recording materials can usually be recognized as a reflected one by providing a colored material on the reverse side of the recording material. However, the image contrast is insufficient merely by providing the colored material on the reverse side of the recording material. Therefore, the formation of a light reflection layer on the reverse side of the recording material is proposed, as disclosed in Japanese Laid-Open Patent Application 1-14079. However, in the case where the light reflection layer is provided on the reverse side of the recording material, images are not always legible depending on the light reflection directions when the images are seen with the naked eyes even though the contrast is remarkably improved in terms of the density and the reflectance thereof measured by a measuring instrument such as a reflection-type densitometer.
When a colored material is provided on the reverse side of the recording material, there is the shortcoming that the image contrast measured by the aforementioned measuring instrument is degraded although images can visually be recognized to some extent regardless of the light reflection directions.